U.S. patent number 7,086,131 [Application Number 11/124,781] was granted by the patent office on 2006-08-08 for deformable mechanical pipe coupling.
This patent grant is currently assigned to Victaulic Company. Invention is credited to Douglas R. Dole, John Gibb, Michael S. Pigott.
United States Patent |
7,086,131 |
Gibb , et al. |
August 8, 2006 |
**Please see images for:
( Reexamination Certificate ) ** |
Deformable mechanical pipe coupling
Abstract
A deformable mechanical pipe coupling is disclosed. The coupling
has a plurality of interconnectable segments that straddle the ends
of pipe elements to be joined. The segments have arcuate surfaces
that engage outer surfaces of the pipe elements. The outer surfaces
subtend an angle of less than 180.degree. and have radii of
curvature greater than the radii of curvature of the pipe element
outer surfaces. The segments have adjustably tightenable connection
members for connecting the segments to one another. When the
connection members are tightened, the arcuate surfaces deform and
conform to the radius of curvature of the outer surface of the pipe
elements.
Inventors: |
Gibb; John (Beeton,
CA), Dole; Douglas R. (Whitehouse Station, NJ),
Pigott; Michael S. (Bluffton, SC) |
Assignee: |
Victaulic Company (Easton,
PA)
|
Family
ID: |
35428975 |
Appl.
No.: |
11/124,781 |
Filed: |
May 9, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050253380 A1 |
Nov 17, 2005 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60571596 |
May 14, 2004 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16L
17/04 (20130101); F16L 23/08 (20130101); F16L
21/02 (20130101); F16L 25/14 (20130101); F16L
21/065 (20130101); F16L 21/005 (20130101); F16L
23/18 (20130101); Y10T 29/53987 (20150115) |
Current International
Class: |
B21D
39/04 (20060101) |
Field of
Search: |
;285/110,111,112,364,420,411 ;29/282 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1051585 |
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Feb 1959 |
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0178360 |
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EP |
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0205896 |
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EP |
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0360946 |
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Apr 1990 |
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EP |
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0412642 |
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Feb 1991 |
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EP |
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0463424 |
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Jan 1992 |
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EP |
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0531833 |
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Mar 1993 |
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EP |
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1180630 |
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Feb 2002 |
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EP |
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2051213 |
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Jan 1981 |
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GB |
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2143294 |
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GB |
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2218768 |
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Nov 1989 |
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GB |
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2253451 |
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Sep 1992 |
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2253452 |
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2367871 |
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Apr 2002 |
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GB |
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WO00/57093 |
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Sep 2000 |
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WO |
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WO01/59350 |
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Aug 2001 |
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WO |
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WO03/029712 |
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Apr 2003 |
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WO |
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Primary Examiner: Bochna; David
Attorney, Agent or Firm: Synnestvedt & Lechner LLP
Claims
What is claimed is:
1. A method of securing facing end portions of pipe elements
together in end-to-end relationship, wherein said end portions of
said pipe elements have an outer surface of substantially
cylindrical profile, said method comprising the steps of: providing
a pipe coupling having a plurality of coupling segments attached to
one another end-to-end surrounding a central space, said coupling
segments having arcuate surfaces adapted to interface with the
outer surfaces of said pipes; inserting said end portions of said
pipe elements into said central space; and deforming said coupling
segments so as to conform the curvature of said arcuate surfaces of
said coupling segments to said outer surfaces of said pipe
elements.
Description
FIELD OF THE INVENTION
This invention concerns mechanical pipe couplings that are
deformable to conform to pipe elements, allowing the couplings to
be pre-assembled and installed as a unit.
BACKGROUND OF THE INVENTION
Mechanical couplings for joining pipe elements together end-to-end
comprise interconnectable segments that are positionable
circumferentially surrounding the end portions of co-axially
aligned pipe elements. The term "pipe element" is used herein to
describe any pipe-like item or component having a pipe like form.
Pipe elements include pipe stock, pipe fittings such as elbows,
caps and tees as well as fluid control components such as valves,
reducers, strainers, restrictors, pressure regulators and the
like.
Each mechanical coupling segment comprises a housing having arcuate
surfaces which project radially inwardly from the housing and
engage plain end pipe elements or circumferential grooves that
extend around each of the pipe elements to be joined. Engagement
between the arcuate surfaces and the pipe elements provides
mechanical restraint to the joint and ensures that the pipe
elements remain coupled even under high internal pressure and
external forces. The housings define an annular channel that
receives a gasket or seal, typically an elastomeric ring which
engages the ends of each pipe element and cooperates with the
segments to provide a fluid tight seal. The segments have
connection members, typically in the form of lugs which project
outwardly from the housings. The lugs are adapted to receive
fasteners, such as nuts and bolts, which are adjustably tightenable
to draw the segments toward one another.
To ensure a good fit between the couplings and the pipe elements,
the arcuate surfaces on prior art couplings have a radius of
curvature that is substantially matched to the radius of curvature
of the outer surface of the pipe element that it is intended to
engage. For couplings used with grooved pipe elements, the radii of
curvature of the arcuate surfaces are smaller than the radii of
curvature of the outer surfaces of the pipe elements outside of the
grooves so that the arcuate surfaces fit within and engage the
grooves properly.
This geometrical relation between the arcuate surfaces of the
couplings and the outer surfaces of the pipe elements in prior art
couplings results in a tedious and time consuming installation
process when mechanical couplings are used. Typically, the coupling
is received by the technician with the segments bolted together and
the ring seal captured within the segments' channels. The
technician first disassembles the coupling by unbolting it, removes
the ring seal, lubricates it (if not pre-lubricated) and places it
around the ends of the pipe elements to be joined. Installation of
the ring seal requires that it be lubricated and stretched to
accommodate the pipe elements, an often difficult and messy task,
as the ring seal is usually stiff and the lubrication makes manual
manipulation of the seal difficult. With the ring seal in place on
both pipe elements, the segments are then placed one at a time
straddling the ends of the pipe elements and capturing the ring
seal against them. During placement, the segments engage the seal,
the arcuate surfaces are aligned with the grooves, the bolts are
inserted through the lugs, the nuts are threaded onto the bolts and
tightened, drawing the coupling segments toward one another,
compressing the seal and engaging the arcuate surface within the
grooves.
As evident from the previous description, installation of
mechanical pipe couplings according to the prior art requires that
the technician typically handle at least seven individual piece
parts (and more when the coupling has more than two segments), and
must totally disassemble and reassemble the coupling. Significant
time, effort and expense would be saved if the technician could
install a mechanical pipe coupling without first totally
disassembling it and then reassembling it, piece by piece.
SUMMARY OF THE INVENTION
The invention concerns interconnectable pipe coupling segments.
Each segment is positionable straddling facing end portions of a
pair of pipe elements for securing the pipe elements together in
end-to-end relationship. The end portions of the pipe elements have
an outer surface of substantially cylindrical profile. Each segment
comprises a pair of arcuate surfaces adapted to interface with the
outer surfaces of the pipe elements. The arcuate surfaces are in
spaced apart relation to one another. The arcuate surfaces subtend
an angle of less than 180.degree. and having a radius of curvature
greater than the radius of curvature of the outer surfaces of the
pipe elements. Each segment further includes connection members for
adjustably connecting one coupling segment to another. The
connection members are adjustably tightenable for drawing the
arcuate surfaces of the segments together. The segments are
deformable upon adjustable tightening of the connection members so
as to conform the curvature of the arcuate surfaces to the outer
surfaces of the pipe elements.
Preferably, the segments are substantially elastically deformable,
and the arcuate surfaces project radially inwardly from the
segments. The connection members comprise a pair of projections
extending outwardly from the ends of each of the segments. The
projections are adapted to receive fasteners for adjustably
connecting the segments to one another, the fasteners being
adjustably tightenable for drawing the arcuate surfaces of the
segments together into engagement with the outer surfaces of the
pipe elements. Preferably, the projections comprise lugs having an
aperture therethrough adapted to receive the fastener.
The invention also concerns a pipe coupling positionable straddling
facing end portions of a pair of pipe elements for securing the
pipe elements together in end-to-end relationship. Again, the end
portions of the pipe elements have an outer surface of
substantially cylindrical profile. The pipe coupling comprises
first and second coupling segments. Each coupling segment has a
pair of arcuate surfaces adapted to interface with the outer
surfaces of the pipe elements. The arcuate surfaces are in spaced
apart relation to one another. The arcuate surfaces subtend an
angle of less than 180.degree. and have a radius of curvature
greater than the radius of curvature of the outer surfaces of the
pipe elements. Each coupling segment has connection members for
adjustably connecting one coupling segment to another. The
connection members are adjustably tightenable for drawing the
arcuate surfaces of the segments together. The segments are
deformable upon adjustable tightening of the connection members so
as to substantially conform the curvature of the arcuate surfaces
to the outer surfaces of the pipe elements.
A pipe coupling also includes a flexible, resilient seal. The seal
is preferably a substantially circular ring having an inner
diameter sized to receive the pipe elements. The seal is positioned
between the arcuate surfaces of the first and second coupling
segments. The seal has an outer diameter sized to position the
first and second coupling segments in spaced apart relation from
one another far enough to thereby allow the pipe elements to be
inserted between the first and second coupling segments into
end-to-end relationship. The seal is deformable when the connection
members are adjustably tightened to draw the arcuate surfaces
together and conform the curvature of the segments to the outer
surfaces of the pipe elements.
Preferably, each of the first and second segments further comprises
a pair of angularly oriented surfaces positioned adjacent to each
of the connection members. The angularly oriented surfaces on each
segment have opposite slopes. The angularly oriented surfaces on
one segment are in facing relation with the angularly oriented
surfaces on the other segment. The angularly oriented segments
engage one another when the segments are drawn together and cause
the segments to rotate relatively to one another about an axis
substantially perpendicular to the pipe elements. The drawing
together and rotation of the segments forces engagement between the
arcuate surfaces and the grooves to provide rigidity about all axes
of the joint.
In another embodiment, a pipe coupling comprises an arcuate band
having first and second ends in substantially facing relation. The
ends are spaced apart from one another. The band surrounds and
defines a central space. First and second arcuate surfaces are
mounted lengthwise along the band on a side thereof. The arcuate
surfaces are in spaced relation alongside one another and project
substantially radially inwardly into the central space. The arcuate
surfaces have a radius of curvature greater than the radius of
curvature of the outer surfaces of the pipe elements. The end
portions of the pipe elements are insertable into the central
space. Connection members are mounted on the first and second ends
of the segments. The connection members are adjustably tightenable
for drawing the first and second ends toward one another. The band
is deformable, allowing the first and second ends to move toward
one another upon adjustable tightening of the connection members.
The arcuate surfaces are thereby brought into engagement with the
outer surfaces of the pipe elements, their curvature substantially
conforming to the curvature of the outer surfaces of the pipe
elements.
Deformation of the band may be elastic, plastic, or may be
facilitated by a hinge positioned between the first and second
ends. The hinge allows a first portion of the band to pivot
relatively to a second portion of the band for receiving the pipes
within the central space.
The invention also includes a method of securing facing end
portions of pipe elements together in end-to-end relationship. The
method comprises the steps of:
(A) providing a pipe coupling having a plurality of coupling
segments attached to one another end-to-end surrounding a central
space, the coupling segments having arcuate surfaces adapted to
interface with the outer surfaces of the pipes;
(B) inserting the end portions of the pipe elements into the
central space; and
(C) deforming the coupling segments so as to conform the curvature
of the arcuate surfaces of the coupling segments to the outer
surfaces of the pipe elements.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 1B are longitudinal cross-sectional views of a deformable
mechanical pipe coupling according to the invention;
FIGS. 2 and 3 are partial cross-sectional views of the pipe
coupling shown in FIG. 1;
FIGS. 4 and 5 are perspective views, partially cut away, of seals
used with pipe couplings according to the invention;
FIGS. 6 7 and 8 are axial views of various pipe coupling
embodiments according to the invention;
FIGS. 7A and 9 13 are longitudinal sectional views of pipe coupling
embodiments according to the invention;
FIG. 14 is a perspective view of a pipe coupling according to the
invention;
FIG. 15 is a side view of the pipe coupling shown in FIG. 14;
FIG. 16 is a cross-sectional view taken at line 16--16 in FIG.
14;
FIG. 17 is an axial view, partially cut away, of pipe coupling
embodiment according to the invention;
FIG. 18 is an axial view of a pipe coupling embodiment according to
the invention;
FIG. 19 is an axial view of a pipe coupling embodiment according to
the invention;
FIG. 20 is an axial view, partially cut away, of a pipe coupling
embodiment according to the invention;
FIG. 21 is a partial sectional view of the pipe coupling shown in
FIG. 20;
FIG. 22 is an axial view, partially cut away, of a pipe coupling
embodiment according to the invention;
FIG. 23 is an axial view of a pipe coupling embodiment according to
the invention; and
FIGS. 24 26 are axial views of a pipe coupling embodiments
according to the invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
FIGS. 1 and 2 show a pipe coupling 10 according to the invention.
Coupling 10 is formed from coupling segments 12 and 14 which are
interconnectable with one another to straddle end portions 16a and
18a of pipe elements 16 and 18 to secure the pipe elements together
in end-to-end relationship. The end portions of the pipe elements
have respective outer surfaces 20 and 22 of substantially
cylindrical profile.
Interconnection of the coupling segments 12 and 14 is effected by
connection members, preferably in the form of lugs 24 and 26 best
shown in FIG. 2. The lugs are preferably positioned at each end of
each segment and project outwardly from the segments. Lugs 24 and
26 are positioned in facing relation to one another and adapted to
receive fasteners, preferably in the form of bolts 28 and nuts 30
which are adjustably tightenable and cooperate with the lugs 24 and
26 for adjustably connecting the coupling segments to one another
as discussed in further detail below.
As best shown in FIG. 1, each segment 12 and 14 comprises a pair of
arcuate surfaces 32 and 34. The arcuate surfaces are in spaced
apart relation to one another and preferably project radially
inwardly toward the pipe elements 16 and 18. The surfaces extend
from a housing 36 having sidewalls 38 joined to a backwall 40, the
sidewalls and backwall forming a channel 42 that receives a seal
44.
Examples of seals 44 are shown in FIGS. 4 and 5. Seal 44 is
preferably a flexible, resilient ring formed from elastomeric
material. The seal may have lips 46 that use the internal pressure
within the pipes to increase the sealing force between the seal and
the outer surfaces 20 and 22 of the pipe elements 16 and 18. As
shown in FIG. 5, seal 44 may also have a tongue 48 positioned
between the lips 46, the tongue extending circumferentially around
the seal and projecting radially inwardly. Tongue 48 provides a
stop surface that engages the ends of pipe elements 16 and 18 to
ensure proper positioning of the seal 44 relatively to the pipe
elements as described in detail below. Engagement of the pipe
elements with tongue 48 also effects alignment of the arcuate
surfaces with the grooves (if present), or with alignment marks on
the outside surface of the pipe elements.
As illustrated in FIG. 2, arcuate surfaces 32 and 34 have radii of
curvature 50 greater than the radii of curvature 52 of the outer
surfaces 20 and 22 of pipe elements 16 and 18. Furthermore, the
arcuate surfaces 32 subtend an angle 54 of less than 180.degree..
Angles 54 between about 40.degree. and about 179.degree. are
practical. As a result of this arcuate surface geometry, segments
12 and 14 may be pre-assembled separated from one another such that
pipe elements 16 and 18 may be inserted directly into the coupling
10 as shown in FIG. 1 without first disassembling the coupling.
This feature provides a significant advantage over prior art
couplings which must be assembled onto the pipe ends piece by
piece. Joining of the pipe ends with a coupling 10 according to the
invention proceeds much more smoothly and quickly than with prior
art couplings because the technician handles fewer pieces and does
not have to thread nuts onto bolts. In the embodiment shown in FIG.
1, the seal 44 has an outer diameter 56 sized to hold the coupling
segments 12 and 14 in spaced apart relation sufficient to allow the
pipe ends to be inserted as described above. The seal inner
diameter 58 is sized to receive the end portions 16a and 18a of the
pipe elements simply by pushing the coupling over the pipe element
or by inserting the pipe elements into the coupling. Other
embodiments having different features for supporting the segments
in spaced relation are described below.
After both pipe elements 16 and 18 are inserted into coupling 10 as
shown in FIG. 1A, nuts 30 are tightened (see also FIG. 2). The nuts
30 cooperate with their bolts 28 to draw the arcuate surfaces 32
and 34 on segment 12 toward those on segment 14. Tightening of the
nuts exerts a force on the lugs 24 and 26 which brings the segments
into contact with the pipe elements and causes the segments 12 and
14 to deform such that the radius of curvature 50 of the arcuate
surfaces 32 and 34 substantially conforms to the radius of
curvature 52 of the pipe elements 16 and 18. This action is
illustrated by comparing FIGS. 2 and 3 and 1A and 1B, wherein the
gap 60 between the arcuate surfaces and the pipe outer surfaces
diminishes as the arcuate surfaces are brought into engagement with
the outer surfaces of the pipe ends. Deformation of the segments 12
and 14 is preferably substantially elastic, allowing the segments
to spring back substantially to their original shape when the nuts
30 are loosened, thereby permitting the coupling 10 to be reused in
the manner according to the invention as described herein. The
segments may also be designed to have significant plastic
deformation, wherein the deformation imparts a permanent set to the
segments. For practical couplings, there will generally be some
degree of both plastic and elastic deformation occurring in the
segments as a result of tightening the fasteners. Additionally,
when the segments 12 and 14 are in the undeformed state (FIG. 2),
the lugs 24 and 26 may be angularly oriented in relation to one
another. Relative angles 62 up to about 10.degree. are practical.
As shown in FIG. 3, the relative angular orientation of the lugs 24
and 26 is reduced as the segments are deformed, and the geometry
may be designed such that the lugs are substantially parallel once
the arcuate surfaces 32 and 34 substantially conform to the outer
surfaces 20 and 22. This is preferred because, when fully
tightened, the bolt head and nut will be in substantially flat
contact with the lugs, thereby avoiding induced bending moments in
the bolts which can cause permanent deformation of the bolts. The
seal 44 is also deformed by this process, as shown in FIG. 1B, with
the lips 46 coming into full engagement with the pipe element outer
surfaces 20 and 22. Because the seal 44 is substantially
incompressible, it must be provided with space into which it may
expand when compressed by the segments. This space is provided by a
concavity 64 positioned in the backwall 40 between the sidewalls
38. Concavity 64 may take virtually any practical shape and allows
for volume change of the seal when it is heated or exposed to
fluids thereby distributing the deformation of the seal more evenly
over its circumference and mitigating the tendency of the seal to
extrude outwardly from between the segments between the lugs. The
concavity also prevents tongue 48, if present, from being forced
between the ends of the pipe elements and impede flow
therethrough.
As shown in FIGS. 2 and 3, for the preassembled coupling 10, it is
advantageous to hold nuts 30 in a position on bolts 28 that will
maintain the segments 12 and 14 in the desired spaced apart
relation as determined by contact between the segments and the seal
44. This is conveniently accomplished by deforming the threads 29
of bolts 28, preferably by staking. Staking the bolts hinders the
rotation of the nuts and prevents them from unscrewing from the
bolts under the effect of vibration, for example, during shipping,
and keeps the coupling in the preassembled state with all of its
parts together prior to installation. The staking is readily
overcome when the nuts are tightened with a wrench.
The bending stiffness of the segments may be tuned to control the
amount of force necessary to deform them in order to reduce the
required assembly torque and mitigate galling between the nut and
the lug. As shown in FIG. 6, sections of increased bending
flexibility 66 may be formed in the housing 36 of the segments 12
and 14 by reducing the area moment of inertia of the segment. This
reduction is preferably achieved by adding one or more cut-outs 68
in either or both the backwall 40 and the arcuate surfaces 32 and
34.
Alternately, as shown in FIG. 7, the segments may have arcuate
surfaces 32 and 34 (not shown) comprising inwardly projecting teeth
69. Teeth 69 engage outer surfaces of the pipe elements to provide
mechanical restraint, and are especially advantageous when used
with plain end pipe elements. Teeth 69 may be substantially
continuous, as shown on segment 14, or intermittent, as shown on
segment 12. Single teeth, preferable for small couplings, are also
feasible. As shown in FIG. 7A, teeth 69 may also be arranged in
pairs on opposite sides of the segment to increase the mechanical
restraint provided by the coupling.
Although couplings according to the invention are described above
as comprised of two segments, this is by way of example only.
Couplings with more than two segments are feasible and preferred
for larger diameter pipes due to the manufacturing costs, as
reducing the size of the segments is economically advantageous. A
further advantage is that the spacing between the lugs is reduced,
requiring fewer turns of the nut and shorter bolts. Standard depth
sockets may thereby be used during installation. FIG. 8 shows an
example of a coupling embodiment 72 having four segments 74 similar
to those described above.
Couplings have thus far been shown wherein all of the arcuate
surfaces have substantially the same radius of curvature. Whereas
such a configuration is appropriate for joining pipes having
substantially the same diameter to one another, FIG. 9 shows a
coupling embodiment 76 for coupling pipe elements of different
diameters. Coupling 76 is formed of two segments 78 and 80
(although it may have more than two segments). Each segment has a
first arcuate surface 82 having a first radius of curvature 84, and
a second arcuate surface 86 having a second radius of curvature 88
smaller than the first radius of curvature 84. This allows coupling
76 to join a pipe element 90 having a larger diameter to a pipe
element 92 having a smaller diameter. Analogous to the couplings
described above, the radius of curvature 84 is greater than the
radius of curvature of the outer surface of pipe element 90, and
the radius of curvature 88 is greater than the radius of curvature
of the pipe element 92. This geometric relationship allows the pipe
elements 90 and 92 to be inserted into a pre-assembled coupling 76
and achieve the advantages of the invention. The coupling segments
78 and 80 deform upon the application of force by adjustable
connection members to conform the radii of curvature to the outer
surface of the pipe elements.
In a preferred embodiment, shown in FIG. 10, the inwardly
projecting arcuate surfaces 32 and 34 of coupling 10 engage grooves
94 formed in the outer surfaces 20 and 22 of pipe element end
portions 16a and 18a. Interaction between the arcuate surfaces 32
and 34 with their respective grooves 94 permits the coupling to
provide relatively high end restraint to withstand forces caused by
internal pressure or external loads. To obtain higher end
restraint, it is found useful to add a second set of arcuate
surfaces that interact with a second set of grooves in the pipe
elements. This embodiment is illustrated in FIG. 11, wherein a
coupling 96 is comprised of segments 98 and 100, each segment
having two pairs of arcuate surfaces 102 and 104 that project
inwardly from the segments. The arcuate surface pairs are in
substantially parallel, spaced relation to one another and engage
pairs of grooves 106 in the surfaces of the pipe elements 108 and
110 which they connect together.
In another embodiment, shown in FIG. 12, couplings according to the
invention such as 10 may be used with pipe elements 112 and 114
having raised circumferential shoulders 116 that are engaged by the
arcuate surfaces 32 and 34 of the segments 12 and 14. Alternately,
as shown in FIG. 13, a coupling 118 according to the invention
having segments 120 and 122 with respective arcuate surfaces 124
and 126 is used with pipe elements 128 and 130 having flared end
portions 132 and 134. Note that in the example embodiments shown in
FIGS. 9 13, the seal 44 has the tongue 48 which is effectively used
to position the pipe ends within the coupling upon insertion, the
tongue acting as a pipe stop to aid in locating the pipe ends at
the proper depth within the couplings.
Another coupling embodiment 136 is shown in FIG. 14. Coupling 136
is comprised of two segments 138 and 140 from which lugs 142 and
144 extend, the lugs cooperating with fasteners 146 to act as
connection members for adjustably connecting one coupling segment
to another. As described above, each segment has a pair of arcuate
surfaces 148, 150, each preferably projecting radially inwardly
from the segments. The arcuate surfaces subtend an angle 152 less
than 180.degree. and have a radius of curvature 154 greater than
the radius of curvature of the pipe elements which the coupling is
to join together. Anti-rotation teeth 70 are positioned adjacent to
the arcuate surfaces and project radially inwardly to engage the
pipe elements and provide torsional rigidity.
As best shown in FIG. 14, each segment 138 and 140 has a pair of
angularly oriented surface portions 156 and 158 located adjacent to
each of the lugs 142 and 144. As illustrated, the slope of surface
portion 156 may be opposite to the slope of surface portion 158 on
each segment. (Both surfaces could also be sloped in the same
direction as well.) This opposite slope relationship between the
surfaces on a segment results in surfaces having compatible slopes
being positioned in facing relation in a pre-assembled coupling as
shown in FIG. 15. When the fasteners 146 are tightened, conforming
the arcuate surfaces to the outer surfaces of the pipe elements,
the angular surface portions 156 and 158 on each segment engage and
slide relatively to one another, causing the segments to draw
together and rotate relatively to one another in opposite
directions about an axis 160 oriented substantially perpendicularly
to the axis of the pipe elements being joined. These motions of the
segments 138 and 140 causes the arcuate surfaces 148 and 150 to
engage grooves in the pipe elements and adds rigidity to all axes
of the joint as previously described. For coupling segments having
surface portions with the same slopes, the couplings move along the
pipe in opposite directions relatively to one another with similar
effect.
As shown in cross section in FIG. 16, the segments 138 and 140
forming the coupling 136 have a channel 162 defined by a housing
164. The housing is formed from a back wall 166 and sidewalls 168,
and receives a seal 170 which is sized to position the segments 138
and 140 in spaced apart relation so as to allow insertion of pipe
elements into the pre-assembled coupling shown in FIG. 14. A
concavity 172 is provided in the back wall to provide a space for
volume change of the seal when it is heated or exposed to fluids as
well as to prevent tongue 48 from being forced between the ends of
the pipe elements and impede flow therethrough due to compression
of the seal.
In another coupling embodiment, shown in FIG. 17, the coupling 174
again is comprised of at least two coupling segments 176 and 178,
each having inwardly projecting arcuate surfaces 180 as described
above. However, arcuate surfaces 180 have notches 182 and 184
positioned at opposite ends. The notches 182 and 184 provide
clearance at the 3 o'clock and 9 o'clock positions of the coupling
where it is most needed to permit pipe elements to be inserted into
the pre-assembled coupling 174. The availability of increased
clearance at these locations allows the coupling segments 176 and
178 to be spaced closer to one another in the pre-assembled
configuration than would be the case if the clearance was not
available at the ends of the surfaces. By having the segments of
the preassembled coupling closer together, the amount of
deformation required to conform the arcuate surfaces to the pipe
element outer surface is reduced and thereby the energy required to
tighten the fasteners.
Another coupling embodiment 192 according to the invention is shown
in FIG. 18. Coupling 192 comprises an arcuate band 194 surrounding
a central space 196. Band 194 has opposite ends 198 and 200
positioned in facing relation to one another. Ends 198 and 200 are
in spaced relation in the pre-assembled coupling and have
connection members mounted thereon, preferably in the form of
projecting lugs 202 and 204 adapted to receive a fastener such as
bolt 206 and nut 208. The bolt and nut cooperate with the lugs to
deform the band 194 and bring the ends 198 and 200 toward one
another after pipe elements have been inserted into the central
space 196 for coupling in end-to-end relationship. Band 194 has a
pair of arcuate surfaces 210, only one of which is visible in the
figure. The arcuate surfaces are in spaced relation lengthwise of
one another as illustrated in FIG. 10 and described above for other
embodiments. The arcuate surfaces 210 have a greater radius of
curvature than the outer surface of the pipe ends that the coupling
is to join together. This geometric configuration, and the
separation of the ends 198 and 200 allows the pipe elements to be
inserted into central space 196. Upon tightening of the nut 208 the
band 194 is deformed such that the radius of curvature of the
arcuate surfaces 210 are forced to conform with the radius of
curvature of the outside surface of the pipe elements which they
engage. Note that in the preassembled state, projecting lugs 202
and 204 are preferably angularly oriented with respect to one
another, having a relative angle 212 up to about 20.degree..
Tightening of the fastener draws the lugs toward each other, and
results in decreasing the relative angle 212, preferably to the
point wherein the lugs are substantially parallel to one another.
This is particularly advantageous for a flexible coupling which
does not depend upon the pipe elements to form a reaction point to
cause the deformation in combination with the bolts, the friction
incurred at the reaction points inhibiting flexibility.
Coupling 192 includes a seal 214 positioned within the band 194
between the arcuate surfaces 210. Seal 214 may be similar to those
illustrated in FIGS. 4 and 5 and sized to receive the pipe elements
for creating a fluid tight seal when the band is deformed.
The bending flexibility of coupling 192 may be adjusted by reducing
the area moment of inertia of band 194. Such adjustments may be
effected by positioning cut-outs 216 in the band. Alternately, as
shown in FIG. 19, a hinge 218 may be provided between the ends 198
and 200. Hinge 218 is preferably positioned equidistant from the
ends of the band and provides infinite bending flexibility,
reducing the torque needed on the fastener to draw the ends 198 and
200 toward one another. The band 194 will still deform as the
arcuate surfaces 210 engage the outer surfaces of pipe elements to
conform the radii of the surfaces with that of the pipe element
outer surfaces. When the hinge is present, the seal 214 is sized so
as to maintain the lugs 202 and 204 in spaced relation so that pipe
elements may be inserted. For both the hinged and hingeless
versions of the coupling described above, the arcuate surfaces
preferably project radially inwardly from the band and may have
different radii of curvature from each other, as illustrated in
FIG. 9, to allow the coupling 192 to be used to join pipes having
different diameters.
FIG. 20 illustrates a pre-assembled coupling 220 that does not
depend on the seal 222 to maintain its segments 224 and 226 in
spaced apart relation and ready to receive pipe elements such as
228. Coupling 220 has spacers 230 that extend between segments 224
and 226 and maintain the segments in spaced apart relation. In this
example embodiment, the spacers 230 comprise collapsible tubes 232
that are positioned between facing lugs 234 and 236 that extend
from the segments. Tubes 232 are preferably thin walled and
circular in cross section and are arranged coaxially surrounding
the fasteners 238. The tubes may be made of lightweight metal or a
polymer material such as polypropylene and may have score lines 240
in their surface to create weakened regions that facilitate
collapse of the tube under compressive loads applied by the
fasteners 238. Other materials, such as cardboard and rubber are
also feasible. The tubes are designed to be strong enough to
support the segments in spaced relation during shipping, handling
and installation, but collapse at a predetermined compressive load
that a technician may apply, preferably by manually tightening the
fasteners with a wrench.
In use, pipe elements to be joined end-to-end are inserted between
the segments 224 and 226. Fasteners 238 are then tightened to draw
the segments toward each other and into engagement with the pipe
elements. Tightening of the fasteners places the tubes 232 under a
compressive load, and the tubes buckle and collapse as shown in
FIG. 21 when the predetermined load is achieved to allow the
segments to move toward one another and engage the pipe elements to
effect the joint.
Spacers positioned between the segments may be used with any type
of mechanical coupling. Note that in FIGS. 20 and 21, the segments
224 and 226 have arcuate surfaces 242 with a radius of curvature
that is substantially the same as the radius of curvature of the
outer surface of pipe element 228 which they are designed to
engage. To provide clearance between the pipe element 228 and the
segments allowing the pipe element to be inserted into the coupling
while still maintaining a reasonable fastener length, notches 244
and 246 are positioned at opposite ends of the arcuate surfaces 242
as best shown in FIG. 20. The notches provide clearance at the 3
o'clock and 9 o'clock positions of the coupling to permit pipe
elements to be inserted into the pre-assembled coupling 220.
FIG. 22 illustrates another coupling embodiment 254 having spacers
230 between segments 256 and 258 comprising the coupling. In this
example, the spacers 230 comprise tubes 260 again positioned
coaxially with fasteners 262 and between facing lugs 264 and 266
projecting from the segments. Tubes 260 have corrugations 268 which
facilitate their collapse when compressive load is applied by
tightening the fasteners. Note that the segments 256 and 258 are
similar to those described above with respect to FIGS. 1 and 2,
wherein the arcuate surfaces of the segments have a greater radius
of curvature than the pipe elements.
Another example of a spacer for maintaining coupling segments in
spaced relation is shown in FIG. 23. Coupling 270 is comprised of
segments 272 and 274 having outwardly projecting lugs 266 and 268
positioned in facing relation when the coupling is pre-assembled.
The segments are held together by fasteners 280 extending between
the lugs. Spacers 282, preferably in the form of block-shaped
bodies 284, are positioned between the lugs 266 and 268. The bodies
284 are removable from between the lugs to allow the fasteners to
be tightened and draw the segments into engagement with pipe
elements being joined.
Bodies 284 may be releasably attached to the segments, for example,
held by friction between the lugs 266 and 268. Flexible, resilient
materials are particularly advantageous for forming the bodies
because bodies made from such materials provide adequate strength
and stiffness to maintain the couplings in spaced apart relation
during rough handling but may be readily deformed for easy removal
as required. If polymer materials are used to form the bodies they
may be adhered to the lugs by heat fusing or by adhesives which
afford a releasable bond between the bodies and the segments.
FIG. 24 illustrates a non-deformable coupling embodiment 286 that
uses spacers 288 to maintain coupling segments 290 and 292 in
spaced apart relation so that pipe elements may be inserted between
them in the preassembled state shown. Coupling 286 has no notches
or other features that provide clearance facilitating inserting
pipe elements into end to end relation between the segments, but
relies on the spacers to provide sufficient separation for adequate
clearance. The spacers 288 may be similar to those described
above.
Spacers according to the invention may also be used with various
other types of couplings. As shown in FIG. 19, a spacer 288 may be
used with the hinged coupling embodiment 192 to keep the lugs 202
and 204 in spaced apart relation so that pipe elements may be
inserted. Although a tubular spacer is illustrated, it is
understood that any of the spacers described herein are feasible
for use with this coupling.
FIG. 25 illustrates an adapter coupling 294 for joining flanged
pipe to non-flanged pipe, for example, grooved or plain end.
Coupling 294 comprises coupling segments 296 and 298, each of which
has a radially extending flange 300 on one side and a arcuate
surface 302 on the opposite side. Segments 296 and 298 are held in
spaced apart relation by spacers 304, which may comprise a
collapsible tubular spacer 306 or a removable spacer 308, or other
types of spacers described herein.
FIG. 26 illustrates further types of spacer embodiments 310
feasible for maintaining coupling segments 312 and 314 in spaced
apart relation. Spacers 310 comprise spring elements which deform,
preferably substantially elastically, when subjected to a
compression force by the fasteners 316. Spring elements may take
any of a number of forms, for example, a rubber cylinder 318 or a
coil spring 320. The use of spring elements for spacers allows for
fine control of the forces required to draw the segments toward one
another and also facilitates the reuse of the couplings when the
deformation of the spring elements is substantially elastic.
It is anticipated that deformable couplings may also include
features such as the tongue and recess disclosed in U.S. Pat. Nos.
6,170,884 and 6,302,450; outlets incorporated within a segment as
disclosed in U.S. Pat. No. 3,362,730; plain end couplings that do
not use grooves as disclosed in U.S. Pat. Nos. 2,439,979,
3,024,046, 5,911,446 and 6,302,450, all of these patents being
hereby incorporated by reference herein.
Deformable mechanical pipe couplings according to the invention
provide for rapid and sure installation creating a pipe joint while
avoiding the need to partially or totally disassemble and then
reassemble the coupling and handle the individual piece parts.
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